Formoterol attenuates neutrophilic airway inflammation in asthma

STUDY OBJECTIVES: Airway neutrophil levels are increased in patients with severe asthma and during asthma exacerbations. Long-acting beta2-agonists (LABAs), such as formoterol, reduce the number of asthma exacerbations. While beta2-agonists may affect neutrophil function in vitro, it is uncertain whether they have effects on neutrophilic inflammation in asthmatic patients in vivo. DESIGN: In a double-blind randomized crossover study, we evaluated the effects of 4 weeks of treatment with formoterol (Turbuhaler), 24 microg bid, compared to placebo on sputum neutrophil numbers and interleukin (IL)-8 levels in asthmatic patients. Therapy with budesonide (administered via Turbuhaler), 400 microg bid for 4 weeks, was added at the end as a "gold standard" antiinflammatory effect comparison. PATIENTS: We studied 15 steroid-na?ve nonsmoking patients who ranged from 19 to 51 years of age and had mild persistent asthma. RESULTS: Formoterol therapy significantly reduced sputum IL-8 levels and neutrophil numbers compared to placebo. There was a significant correlation between the reduction in sputum IL-8 levels and the number of neutrophils, indicating that formoterol may attenuate neutrophilic airway inflammation by inhibiting IL-8 production. CONCLUSIONS: Our data suggest that the LABA formoterol reduces neutrophilic airway inflammation in patients with mild asthma and that this might be beneficial in preventing asthma exacerbations.     

Predictors of neutrophilic airway inflammation in young smokers with asthma

Introduction: Asthma is one of the most widespread chronic diseases worldwide. In spite of numerous detrimental effects on asthma, smoking is common among asthma patients. These smoking-induced aggravations of asthma may be attributed to changes in airway inflammation, which is characterized by a higher degree of neutrophilic inflammation than in non-smokers. A state of neutrophilic inflammation may lead to increased steroid resistance and an accelerated loss of lung function owing to tissue destruction. The aim of this study was to elucidate predictors of neutrophilic inflammation in young asthmatic smokers not on steroid treatment, including analysis of tobacco history and bacterial colonization. Methods: In a cross-sectional study, 52 steroid-free, current smokers with asthma were examined with induced sputum, fractional exhaled nitric oxide (FeNO), lung function, ACQ6 score, mannitol and methacholine challenge. A sample from the sputum induction was taken for bacterial analysis using 16S gene PCR technique and sequencing. Results: Using one-way analysis of variance and binary and linear regression models, only age and ACQ6 score were found to be significant predictors for airway neutrophilia. The investigation also included analysis for effect of pack years, current tobacco consumption, body mass index, lung function, FeNO; methacholine and mannitol responsiveness, atopy, gender, asthma history and presence of bacteria. The most common potentially pathogenic bacteria found were Streptococcus spp., Haemophilus spp. and Mycoplasma spp. Conclusion: In this study, no tobacco-related predictors of airway neutrophilia were found, indicating that in the younger years of asthma patients who smoke, the amount of tobacco smoked in life does not influence the degree of neutrophilia. Conversely, for asthmatic smokers, neutrophilia may be induced when a certain threshold of tobacco consumption is reached.     

Association between neutrophilic airway inflammation and airflow limitation in adults with asthma

BACKGROUND: There is debate about the mechanisms of persistent airflow limitation in patients with asthma. Chronic inflammation is assumed to be important, although there is limited and contradictory information about the relationship between airway inflammation and postbronchodilator FEV1. METHODS: We have assessed the cross-sectional relationship between prebronchodilator and postbronchodilator FEV1 and measures of airway inflammation after allowing for the effects of potential confounding factors. Multivariate analysis was performed on data collected from 1,197 consecutive patients with asthma seen at the respiratory outpatient clinic at Glenfield Hospital between 1997 and 2004. Relationships between induced sputum total neutrophil and differential eosinophil cell counts, and prebronchodilator and postbronchodilator lung function were examined. RESULTS: Sputum total neutrophil but not differential eosinophil count was associated with lower postbronchodilator FEV1. Both differential eosinophil and total neutrophil count were associated with lower prebronchodilator FEV1. These effects were independent after adjustment for age, smoking, ethnicity, asthma duration, and inhaled corticosteroid use. A 10-fold increase in neutrophil count was associated with a 92 mL reduction (95% confidence interval, 29 to 158; p = 0.007) in postbronchodilator FEV1. CONCLUSIONS: In this large heterogeneous population of adults with asthma, we have shown that prebronchodilator FEV1 is associated with neutrophilic and eosinophilic airway inflammation, whereas sputum total neutrophil counts alone are associated with postbronchodilator FEV1. This supports the hypothesis that neutrophilic airway inflammation has a role in the progression of persistent airflow limitation in asthma and raises the possibility that this progression and the development of COPD share a common mechanism.     

Loss of control of asthma following inhaled corticosteroid withdrawal is associated with increased sputum interleukin-8 and neutrophils

BACKGROUND: The role of neutrophils in exacerbations of asthma is poorly understood. We examined the effect of withdrawal of inhaled corticosteroids on sputum inflammatory indexes in a double-blind study in patients with moderate, stable asthma. METHODS: Following a 2-week run in period, 24 subjects were randomized to receive either budesonide (400 microg bid) or placebo, and the study was continued for another 10 weeks. RESULTS: Loss of asthma control developed in 8 of 12 patients over the 10-week period of steroid withdrawal, whereas only 1 of 10 patients with budesonide treatment had exacerbations. Those with an exacerbation had increased sputum interleukin (IL)-8 (p < 0.0001) and increased sputum neutrophil numbers (p < 0.0001) compared to those without an exacerbation. The significant elevation in sputum IL-8 and neutrophil counts initially occurred 2 weeks prior to an exacerbation. Sputum neutrophilia correlated positively with changes in IL-8 levels (r(2) = 0.76, p = 0.01). CONCLUSIONS: Rapid withdrawal of inhaled corticosteroids results in an exacerbation of asthma that is preceded by an increase in sputum neutrophils and IL-8 concentrations, in contrast to an increase in eosinophils reported in previous studies in which inhaled steroids are slowly tapered.     

Clinical assessment of asthma severity partially corresponds to sputum eosinophilic airway inflammation

In the aim to evaluate the relationship between sputum eosinophil percentages and eosinophil cationic protein (ECP) concentrations, as markers of airway inflammation, and different Levels of asthma severity, we examined 223 patients consecutively observed in our asthma clinic. Diagnosis of asthma was made according to internationally accepted criteria. Asthma severity was evaluated according to frequency of symptoms, FEV1, peak expiratory flow variability and level of asthma treatment needed to control asthma. Spontaneous or induced sputum was collected. Adequate sputum samples were obtained in 68 untreated subjects and in 117 subjects regularly treated with ICS. A control group of 14 normal subjects was also examined. In untreated subjects, mild intermittent asthmatics showed a lower sputum eosinophil percentage in comparison with other groups of asthma severity, while no difference in ECP levels was detected. In treated subjects, severe asthmatics showed higher levels of sputum eosinophils and ECP in comparison with other groups of asthma severity. Mild persistent and moderate persistent patients did not differ for sputum eosinophils or ECP in both untreated and treated subjects. Controls were significantly different from all groups of untreated and treated asthmatics. In conclusion, the assessment of asthma severity according to clinical and functional findings only partially corresponds to the severity of eosinophilic airway inflammation as assessed by induced sputum analysis.     

嗜酸细胞趋化因子在哮喘、嗜酸细胞性支气管炎患者诱导痰中的表达及其与气道炎症的关系

目的探讨嗜酸细胞趋化因子（eotaxin）在支气管哮喘、嗜酸细胞性支气管炎患者气道炎症发生中的作用以及在两者间的区别。方法分别收集支气管哮喘（A组）、嗜酸细胞性支气管炎（EB组）、单纯慢性支气管炎（CB组）缓解期/稳定期患者13例、11例、12例和健康对照者（C组）9例。诱导痰并经处理后进行分类细胞记数,并用夹心法酶联免疫吸附测定（ELISA）其诱导痰上清液中eotaxin浓度。结果诱导痰嗜酸细胞占白细胞百分比（Eos/Leu%）、eotaxin浓度A组[（19.2±9.7）%;（0.251±0.118）g/L]、EB组[（11.4±6.1）%;（0.146±0.079）g/L]分别与CB组[（0.9±0.6）%;（0.043±0.036）g/L]、C组[（0.8±0.4）%;（0.031±0.013）g/L]比较,差异有显著性（P均〈0.05）;A组Eos/Leu%、eotaxin浓度与EB组比较,差异也有显著性（P均〈0.05）。结论 eotaxin可能通过对Eos的选择性趋化作用参与了支气管哮喘和嗜酸细胞性支气管炎患者气道炎症的发生机制,这种作用机制对于支气管哮喘和嗜酸细胞性支气管炎在程度上可能是不同的。     

Clinical judgement of airway inflammation versus sputum cell counts in patients with asthma.

The inflammatory component of asthma is usually assessed indirectly by symptoms and spirometry, these may be inaccurate. It can now be assessed directly and reliably by the examination of sputum cell counts. There is no information on how clinical assessment of the presence and type of airway inflammation compares with actual measurements. In this single-centre observational study, sputum was collected from 76 consecutive adults with asthma attending a tertiary chest clinic after their physicians had recorded the expected cell counts in sputum. The authors examined the extent of agreement between clinical judgement of sputum cell counts and actual counts in asthmatic patients (Cohen's Kappa) and the possible predictors of agreement (multiple logistic regression). Sixty-seven of the 76 sputum samples were suitable for analysis. Agreement between expected and actual cell counts occurred in 30/67 patients. The overall agreement for the different cell types was poor (estimated K=0.14, 95% confidence interval (CI)=0.02, 0.26). The experience of the physician in using sputum cell counts in clinical practice, steroid requirement at the time of assessment, and control of asthma as assessed by the physician or by the patient could not predict the chances of agreement or disagreement. Unaware of the sputum results, the physicians often changed treatment in a way that seemed inappropriate for the cell counts present. There is poor agreement between clinical judgement of the presence and type of airway inflammation in asthmatic patients and sputum cell counts. The impact of sputum examination on the outcomes of anti-inflammatory treatment now needs investigation.     

Analysis of induced sputum: a new approach to the study of airway inflammation in asthma.

Induced sputum is a simple method that enables the analysis of lower respiratory tract material obtained through non-invasive methods. Validation of the technique for the study of airway inflammation in asthma and other respiratory diseases, together with the most relevant findings reported in the literature, are reviewed herein. Accurate methods that can be applied to the analysis of induced sputum samples, such as immunocytochemistry, flow cytometry or polymerase chain reaction are also discussed.     

重度支气管哮喘患者气道炎症及其与白细胞介素17的关系

目的探讨重度支气管哮喘(简称哮喘)患者气道炎症特征及其可能机制,并进一步观察吸入糖皮质激素治疗对气道炎性细胞分类计数、炎症介质、白细胞介素17(IL-17)和IL-8等细胞因子的影响。方法分别选择轻度(轻度组)、中度(中度组)和重度(重度组)持续哮喘患者16例、14例和18例,正常对照组15名,采用基线评估包括哮喘症状控制评分、肺功能测定和用诱导痰检查方法对痰炎性细胞进行分类计数;采用酶联免疫吸附测定(ELISA)法检测痰IL-17和IL-8浓度;采用酶联免疫荧光法测定嗜酸粒细胞阳离子蛋白(ECP)浓度;采用比色法测定中性粒细胞髓过氧化物酶(MPO)浓度,并用痰液蛋白含量进行校正。然后规范吸入糖皮质激素治疗4周,随访轻、中度和重度哮喘患者各15例复查上述指标。结果痰嗜酸粒细胞(EOS)比值和ECP浓度在每克蛋白中轻度组分别为0.0670±0.0740、(155±91)×10-6g;中度组分别为0.0830±0.0440、(180±83)×10-6g;重度组分别为0.1240±0.1430、(191±87)×10-6g,与正常对照组[0.0000±0.0010、(44±25)×10-6g]比较差异有统计学意义(P<0.01);但各哮喘组间比较差异无统计学意义(P>0.05)。中性粒细胞比值在重度组为0.589±0.203,与轻度组(0.455±0.154)、中度组(0.449±0.194)、正常对照组(0.313±0.134)比较差异有统计学意义(P<0.01)。MPO水平在每克蛋白中,重度组为(31±10)U,轻度组为(12±4)U、中度组为(22±7)U,与正常对照组[(10±4)U]比较差异有统计学意义(P<0.01)。IL-17水平在每克蛋白中重度组为(264±137)×10-9g,中度组为(172±65)×10-9g,轻度组为(126±52)×10-9g,与正常对照组[(56±20)×10-9g]比较差异有统计学意义(P<0.01);IL-8浓度在每克蛋白中,重度组为(531±321)×10-9g,轻度组为(410±181)×10-9g,中度组为(438±148)×10-9g,正常对照组为(83±36)×10-9g,重度组与正常对照组比较差异有统计学意义(P<0.01);而轻度组与中度组间比较差异无统计学意义(P>0.05)。IL-17水平与IL-8、中性粒细胞与MPO呈显著相关(r分别为0.525、0.349、0.602,P均<0.01)。经糖皮质激素治疗后,对轻、中、重度30例哮喘患者进行合并分析表明,EOS、ECP、MPO、IL-17和IL-8均显著降低;但两组患者的中性粒细胞比值在治疗后比较差异均无统计学意义(P>0.05);但重度组(0.642±0.157)与轻、中度哮喘组(0.394±0.147)比较差异有统计学意义(P<0.01)。结论中性粒细胞增多是重度哮喘的气道炎症特征之一,IL-17/IL-8可能参与中性粒细胞向气道内的募集。     

Pharmacology of airway inflammation in asthma

Chronic desquamative eosinophilic bronchitis is a characteristic pathologic feature of asthma which may even antedate the onset of symptoms. The pharmacology of asthmatic inflammation has been relatively poorly studied and most of the current data available have been inferred indirectly from studies of bronchial hyperresponsiveness and late-phase responses. Apart from mast cells, the effects of drugs used in the treatment of asthma on other airway inflammatory cells such as eosinophils, alveolar macrophages, etc. have not been extensively studied. The pharmacology of asthmatic inflammation should comprise the study of various aspects of this inflammatory response such as airway microvascular leakage, mediator release, and cell chemotaxis. Ultimately the pharmacologic modulation of the pathologic features of the asthmatic airway by the chronic use of antiasthma drugs, coupled with clinical responses, need to be investigated using bronchial biopsies and broncholveolar lavage in asthmatic patients.     

Allergic bronchial asthma: airway inflammation and hyperresponsiveness

The international consensus report on diagnosis and treatment of asthma was published in 1992 (Clin Exp Allergy 22: 1-72). According to the report, asthma is a chronic inflammatory disorder of the airways in which many cells play a role, including mast cells and eosinophils. Airway inflammation causes various symptoms of asthma which are usually associated with widespread but variable airflow obstruction and causes an associated increase in airway responsiveness to a variety of stimuli. The definition of asthma, provided in this report, is an epoch-making revision of the conventional recognition of asthma based on respiratory physiology and does not contradict the empirical knowledge that asthma responds well to steroid therapy. One reason, which led airway inflammation to be understood as a major factor in the pathophysiology of asthma is the technological advance and the widespread use of bronchoscopes. The use of bronchoscopy as a research tool has markedly improved the understanding of the pathology of asthma. It became also possible to link biopsy findings to autopsy findings in patients who died of asthma. However, it is relatively difficult to repeat a biopsy of the airway mucosal membranes in individual asthmatic patients. Here, animal models of asthma play a significant role. Findings from animal models can provide a clue for the development of new anti-asthmatic drugs. This paper will deal with the paradigm of allergic asthma and focus on recent topics of interleukin (IL)-4 and IL-5, which seem to play a central role in allergic asthma. The causative relationship between airway inflammation and hyperresponsiveness will be discussed.     

Increased ozone-induced airway neutrophilic inflammation in extracellular-superoxide dismutase null mice

Extracellular-superoxide dismutase (EC-SOD) exists primarily in the tissue interstitium and the lung contains particularly large amounts of the enzyme.To determine the roles of EC-SOD and extracellularly formed superoxide radicals in the pulmonary response to the common air pollutant ozone, wild-type mice and mice lacking EC-SOD were exposed to 1.5 ppm ozone for 48 h. The exposure resulted in a marked neutrophilic inflammatory reaction observed both in the bronchoalveolar lavage fluid (BALF) and by histopathology of the lungs, which was much stronger in the mice lacking EC-SOD. Unlike the wild-type mice, the null mutants also showed increased levels of interleukin-6 in the BALF. The ozone exposure also resulted in increased airway mucosal permeability and cell damage as indicated by increased protein and lactate dehydrogenase in the BALF. There was, however, no difference between the two groups of mice.The results suggest that extracellular superoxide radicals are important inflammatory mediators in the pulmonary response to ozone, but in the present model, the radical and the infiltrating neutrophils contributed little to the pulmonary injury The data, together with previous findings, support a role for EC-SOD as a modulator of inflammatory reactions.     

诱导痰气道炎症指标与支气管哮喘病情关系的探讨

目的 探讨气道炎症指标对支气管哮喘(简称哮喘)患者病情监测及治疗的意义.方法 收集2004年1月至2006年1月在北京大学第三医院呼吸科门诊就诊的近半年来未使用口服或吸入激素治疗的哮喘患者87例.进行哮喘症状评分、肺功能检查、诱导痰上清液检测白介素-8(IL-8)浓度及嗜酸粒细胞阳离子蛋白(ECP)浓度,对所有患者病情分级状况和气道炎症指标进行分析,探讨病情严重程度与气道炎症之间的关系;分析急性发作与气道炎症之间的关系.结果 (1)重度哮喘患者中性粒细胞、IL-8水平较轻中度患者明显增高;(2)急性发作期患者嗜酸性粒细胞(EOS)、ECP较缓解期明显增高;(3)中性粒细胞与第1秒用力呼气量(FEV1)呈负相关(r=-0.522,P＜0.05);中性粒细胞与IL-8呈正相关(r=0.832,P＜0.05);(4)ECP、EOS与FEV1、症状评分均无相关性(r=-0.209,r=-0.189,P均＞0.05;r=-0.289,r=-0.229,P均＞0.05);ECP与EOS呈正相关(r=0.852,P＜0.01);(5)中性粒细胞对重度哮喘的阳性预测值为91%,EOS对哮喘急性发作的阳性预测值为92.5%,ECP对哮喘急性发作的阳性预测值98.5%.结论 (1)中性粒细胞、IL-8与病情严重程度有关,重度哮喘患者中性粒细胞、IL-8明显增高;(2)ECP、EOS与哮喘的急性发作有关,急性发作期哮喘患者ECP、EOS明显增高;(3)气道炎症指标可用于监测哮喘病情和调整哮喘治疗.     

Pharmacology of airway inflammation in asthma and COPD

The current asthma therapies are not cures and symptoms return soon after treatment is stopped even after long term treatment. Although inhaled glucocorticoids are highly effective in controlling airway inflammation in asthma, they are ineffective in the small group of patients with glucocorticoid-dependent and -resistant asthma. With very few exceptions, COPD is caused by tobacco smoking, and smoking cessation is the only truly effective treatment of COPD available. Current pharmacological treatment of COPD is unsatisfactory, as it does not significantly influence the severity of the disease or its natural course. Glucocorticoids are scarcely effective in COPD patients without concomitant asthma. Bronchodilators improves symptoms and quality of life, in COPD patients, but, with the exception of tiotropium, they do not significantly influence the natural course of the disease. Theophylline is the only drug which has been demonstrated to have a significant effect on airway inflammation in patients with COPD. Here we review the pharmacology of currently used antiinflammatory therapies for asthma and COPD and their proposed mechanisms of action. Recent understanding of disease mechanisms in severe steroid-dependent and -resistant asthma and in COPD, has lead to the development of novel compounds, which are in various stages of clinical development. We review the current status of some of these new potential drugs.